(3) 파이썬에서 MQTT 사용하기.

1) MQTT모듈 설치

pip install paho-mqtt

2) 클라이언트가 broker에 접속하는 코드

#!python3
import paho.mqtt.client as mqtt                      #import the client1
import time                                         # connetcion being created and the callback being triggered 해야해서 time.sleep 필요

def on_connect(client, userdata, flags, rc):        # client= 클라이언트 대상 ,rc= 리턴코드
    if rc==0:                                       # 리턴코드=0일때 연결성공/ 1~5는 refused / 6~255 사용안됨
        client.connected_flag=True                  # set flag(연결이 되면 true로 바꿈)
        print("connected OK")
    else:
        print("Bad connection Returned code=",rc)

mqtt.Client.connected_flag=False            # create flag in class
broker="192.168.1.184"                      # broker에 알맞은ip필요
client = mqtt.Client("python1")             # create new instance 
client.on_connect=on_connect                # bind call back function
client.loop_start()                         # start loop
print("Connecting to broker ",broker)
client.connect(broker)                      # connect to broker
while not client.connected_flag:            # wait in loop(wiat for connection setup to complete)// client.connected_flag= True 나오면 안돌아감
    print("In wait loop")
    time.sleep(1)                           
print("in Main Loop")
client.loop_stop()                          # Stop loop 
client.disconnect()                         # disconnect1

3)실행결과